DatasetTransformer throws when is used on its own

[ganik]

Repro:
r0 = Pipeline([MinMaxScaler()])
r0.fit(train_df)

r1 = Pipeline([DatasetTransformer(r0.model)])
r1.fit_transform(train_df) <---- throws here

Traceback (most recent call last):
r1.fit_transform(train_df)
File "E:\sources\tmp\NimbusML\src\python\nimbusml\internal\utils\utils.py", line 220, in wrapper
params = func(*args, **kwargs)
File "E:\sources\tmp\NimbusML\src\python\nimbusml\pipeline.py", line 1132, in fit_transform
**params)
File "E:\sources\tmp\NimbusML\src\python\nimbusml\internal\utils\utils.py", line 220, in wrapper
params = func(*args, **kwargs)
File "E:\sources\tmp\NimbusML\src\python\nimbusml\pipeline.py", line 1051, in fit
X, y, verbose, **params)
File "E:\sources\tmp\NimbusML\src\python\nimbusml\pipeline.py", line 740, in _fit_graph
*(graph_nodes))
File "E:\sources\tmp\NimbusML\src\python\nimbusml\internal\utils\entrypoints.py", line 206, in init
self._set_outputs(outputs)
File "E:\sources\tmp\NimbusML\src\python\nimbusml\internal\utils\entrypoints.py", line 253, in _set_outputs
"outputs from the graph do not match graph_outputs.")
ValueError: outputs from the graph do not match graph_outputs.